The invention relates to devices for spreading and broadcasting materials such as pellet fertilizers, seeds, and the like and more particularly is directed to improvements in a hand-held material broadcasting device of the type disclosed in U.S. Pat. Nos. 3,157,402 and 3,227,461, which patents represent the closest prior art known to applicant.
Devices of the character referred to have been in successful and widespread use. They comprise very briefly a relatively small portable housing having a manually engageable handle for convenient carrying about and proper positioning of the device when in use. The housing provides a storage chamber for flowable granular material such as fertilizer pellets, seeds or the like which is superimposed over a normally horizontally rotating impeller which functions to centrifically throw the material in a fan-shaped area extending from the front of the device and which can be readily directed by the user in the manual orientation of the device. A valve member regulates the flow of the material from the storage chamber to the impeller and has closed, intermediate and full open positions in which the flow of material to the impeller is cut off or regulated to the full flow capacity of the device. A manually displaceable member is positioned adjacent the handle and has a connection to the valve member to effect its displacement from closed position to its fully opened position against the action of a biasing spring normally moving the valve member to its closed position. The operator can select the desired volume output by a manually adjustable means which limits the opening of the valve member and the corresponding degree of movement of the actuating member. When this adjusting means is set to an intermediate output, the movement of the valve actuating member is interrupted, i.e., stopped, at the position corresponding to the desired position of the valve member regulating flow of material from the storage chamber to the impeller. Frequently, in the use of the device set in an intermediate output position, the operator will wish to at least momentarily increase the output flow. He may of course do this by reseting the aforementioned manually adjustable means. However, during operation both hands of the user are occupied, one holding the holding the handle of the device and directing the output spray of material, and the other hand is engaged with a crank driving the impeller. Accordingly, if the operator wishes to readjust the output flow, he need to momentarily release one hand from the crank in order to engage the flow adjustment means to permit further opening movement of the valve member. It has been found from experience, human nature being what it is, that the operator instead of momentarily stopping operation of the device, will try to force a greater flow by pushing harder on the manually displaceable actuating member connected to the valve member. The later, of course, in the design of the unit as above explained, is held against a further opening movement of the valve member by the manually adjustable means limiting the opening movement. In the preferred design the actuating member is disclosed for engagement and displacement by the thumb of the hand holding the handle, and where the operator has sufficient strength, he may in the situation described, bear down so hard on the actuating member as to break its connection to the valve member and thus render the whole device inoperative.